He's played with Barbie dolls on air, claimed Barack Obama is a racist, accused George Soros of collaborating with the Nazis and he foresaw Doomsday a lot, often through spurting tears. And yet, strangely, none of this gave him sufficient news credibility to save him from imminent unemployment.

Glenn Beck – the man so extreme he scared away advertisers devoted to the rest of Fox News – will be folding up his special serious glasses, wiping down the blackboard on which he illustrated so many conspiracy theories, packing up his magic pointer and leaving the building.

This will come as a shame to some, not least comedians Jon Stewart and Stephen Colbert. The male counterpart to Sarah Palin, Beck has been a particularly useful figure for them to illustrate Fox News and the Republican party's careening slide down into extremism and wackiness. Stewart's imitations of Beck were a tour de force of satire.

It will also disappoint those still waiting to find out just how much Beck believed his own spiel. He didn't seem entirely sure, oscillating between describing himself as "the voice of truth" and "an entertainer". This was one of those rare subjects on which he did not display boggle-eyed certainty.

To most, though, who saw him as part of the engine that was debasing not just American news programming but US politics in general, his departure will not be a cause for too many tears. Those will be left to Beck.